Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “SARS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,387 records · Page 77
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Active microwave and millimeter wave SAR remote sensing

This paper presents the performance and interference criteria for spaceborne active sensors, interference mitigation techniques, and allocation considerations for certain frequency bands for the upcoming WRC 2003.

interference studies frequency compatibility studi↗
NASA NTRS1996

Monitoring Tree Moisture Using an Inversion Algorithm Applied to SAR Data from BOREAS

During several field campaigns in spring and summer of '94, the NASA/JPL air-borne sythetic aperature radar (AIRSAR) collected data over the southern and northern study sites of BOREAS. Among the areas over which radar data were collected was the young jack pine tower site, which is generally characterized as have shot but closely space trees with a dense crown layer.

forest canopy moisture↗
NASA NTRS2005

System concepts and technologies for high orbit SAR

This paper discusses large aperture, high orbit radar concepts for measuring sub-centimeter-level surface displacements from space. We will explain the need for large aperture, high orbit arrays and will discuss the technologies required to achieve these missions.

membrane arrays↗
NASA NTRS2001

Motion compensation for ultra wide band SAR

This paper describes an algorithm that combines wavenumber domain processing with a procedure that enables motion compensation to be applied as a function of target range and azimuth angle. First, data are processed with nominal motion compensation applied, partially focusing the image, then the motion compensation of individual subpatches is refined. The results show that the proposed algorithm is effective in compensating for deviations from a straight flight path, from both a performance and a computational efficiency point of view.

Synthetic aperture radar processing motion compens↗
NASA NTRS2011

Techniques and Tools for Estimating Ionospheric Effects in Interferometric and Polarimetric SAR Data

The InSAR Scientific Computing Environment (ISCE) is a flexible, extensible software tool designed for the end-to-end processing and analysis of synthetic aperture radar data. ISCE inherits the core of the ROI_PAC interferometric tool, but contains improvements at all levels of the radar processing chain, including a modular and extensible architecture, new focusing approach, better geocoding of the data, handling of multi-polarization data, radiometric calibration, and estimation and correction of ionospheric effects. In this paper we describe the characteristics of ISCE with emphasis on the ionospheric modules. To detect ionospheric anomalies, ISCE implements the Faraday rotation method using quadpolarimetric images, and the split-spectrum technique using interferometric single-, dual- and quad-polarimetric images. The ability to generate co-registered time series of quad-polarimetric images makes ISCE also an ideal tool to be used for polarimetric-interferometric radar applications.

Ionosphere↗
NASA NTRS2011

Large Aperture, Scanning, L-Band SAR

We have developed the first L-band membrane-based active phased array. The antenna is a 16x16 element patch array with dimensions of 2.3mx2.6m. The array uses membrane-compatible Transmit/Receive (T/R) modules for electronic beam steering. We will discuss the antenna design, the fabrication of this large array, the T/R module development, the signal distribution approach and the measured results of the array

phased array↗
NASA NTRS2012

The 2011 Eco3D Flight Campaign: Vegetation Structure and Biomass Estimation from Simultaneous SAR, Lidar and Radiometer Measurements

The Eco3D campaign was conducted in the Summer of 2011. As part of the campaign three unique and innovative NASA Goddard Space Flight Center airborne sensors were flown simultaneously: The Digital Beamforming Synthetic Aperture Radar (DBSAR), the Slope Imaging Multi-polarization Photon-counting Lidar (SIMPL) and the Cloud Absorption Radiometer (CAR). The campaign covered sites from Quebec to Southern Florida and thereby acquired data over forests ranging from Boreal to tropical wetlands. This paper describes the instruments and sites covered and presents the first images resulting from the campaign.

Fatoyinbo, Temilola↗